Motion picture screen



Feb. 23, 1932. A, 1 RAVEN MOTION PICTURE SCREEN 2 Sheets-Sheet l FiledJan. 4, 1928 Feb. 23, 1932.

A. RAVEN 1,846,357

MOTIN PICTURE SCREEN 2 Sheets-Sheet 2 Filed Jan. 4, 1928 INVENTOR www.WMM

' ,if/S ATTORNEYS Patented Feb. 23,1932

UNITED STA TEs PATENT OFFICE A ALEEET Louis or MOUNT vEENoN, NEW YoExMOTION PICTURE scEEEN le will be of such construction that it will offerl but slight resistance to the passage therethrough of sound waves, airor other gases of -like nature.

In a heretofore customary manner of makingreflecting motion picturescreens the foundation or base ofthe screen is composed of some densematerial preferably of such a nature that little if any light may b'etransmitted therethrough, the rimary object bet ing'to obtain a frontsur ace which will refleet towards the spectators a maximum quantity oflicht without the production of a glare as wouldD be produced by amirrored surface. Various means are utilized to attain this result,.oneway of attaining this is disclosed in my prior Patent No. 1,315,743,dated September 9, 1919. Various expediente are used to preventthereflecting surfaces of these screens from all lying in the sameplane, the object being to attain a diffusion of the reflected light. 4

A methodwhieh has been heretofore proposed to obtain a highly reflectivesurface cpmprises an opaque screen with `a front surface composed ofsome highly refractive material.. A layerof clear crystal glass beads isembedded within this front surface and held in .position by adhesion insuch a manner that substantially one half of the bead is embedded andone halfk is exposed above the existing surface. Each bead then acts asa tiny mirror with a spherical reflecting surface, the light beingtransmitted through-the clear transparent glass to the back of the beadwhere it meets the reflectingl surface and is reflected either back inthe direction from whence it came or is reflected at an angle;Screensmade in this manner are too directional, that is, they do notdiffuse the light sufficiently, vby far the greatest proportionApplication med Tammy 4, 192s. serial No. 244,404.

of the light is reflected nearly in the direction from whence it came.Thus, to one l0- cated near the `projection apparatus, the-illuminationis satisfactory, but to one remote from the line of the projected lightthe illumination is not satisfactor lVith the advent of taxing motionpictures.sueh for example, as the Vitaphone, it has been foundthat whenlarge screens are used with the sound producing horn placed at one sideof the screen, the voice or music does not appear to emanate from .thelogical source of the sound, that is, the picture projected on thescreen. This effect 1s particularly noticeable when an actor in apicture is speaking while in a position adjacent to one margin of thepicture, while the horn of the Vitaphone is located near the oppositemargin of the screen. This effect is not notice able enough to bedisturbing to those `seated in the centre of the theatre and at aconsiderable distance from the screen. It, however, is very pronouncedto one sitting at the side .of the theatre at a considerable angle tothe screen.

' In order to overcome this ldefect it is necessary to replace the usualopaque screen Witha porous cloth screen locating the Vitaphone speakerdirectly behind the screen. The Vporous nature of the cloth screenpermits the passage therethrough of the sound waves and as a consequencethe sound appears to emanate from'the projected picture upon the screen.This method has the very seriousdefect that due to the poroustranslucent nature of the cloth screen. a great portion (about 40%) ofthe light projected thereon passes through the screen and is'lost, thusthe illumination of the piccompensate for this, it is proposed toincrease the candle power ofthe projection appa-l the projectionapparatus also increases the 100 I oo ture is proportionately re ced Inorder to danger of burning or damaging the film as it passes throu h theprojection machine.

In case .the itaphone is only used occasionally and -it is desired tosave current, it

' 5 would be necessary to use two screens of the waves. In the practiceof the invention the' screen is built up ofy layers of opalescent orlmilk glass beads. 'The' layers are suitably spaced from each other andthe beads in each layer so positioned and secured that the beads of eachsucceeding layer are .placed'dir-ectly in front of the intersticialspaces between the 23 beads in the layer directly'behind. A sufficientnumber of layers is used so that there 'for light rays from theprojection apparatus. The intersticial spaces between the beads, 5howeyer, permit the passage of 'air or air borne sound waves. vWhen thescreen iscomposed of three layers of beads the sound waves are able tofind a passage throughl the screen by making one, or at the mosttwo,turns or 3a deviations from a straight course. I have found itadvantageous in forming the screen to use` three layers of beads and touse a different sized bead for each layer. The largest beads are placedin the layer most remote from the spectators. 'Ihe intermediate layer ofbeads is yadvantageously made up of.

beads substantially two thirds the diameter of the larger beads. Thebeads in the layer at the front of the screen, nearest the spectators,11G lare substantiallytwo thirds the diameter of the beads inftheintermediate layer.

l' I have found it advantageousin forming .the layers used in buildingup thebead screen to use beads Inot only lof the conventional sphericalshape but also for4 certain types of screens-to use beads of othershapes. F or certain types. of screens Where it is advantageous toreduce the thickness and/ or weight of the'screens, hemispherical beadsare used.

t) Flattened, ellipsoid or disc shaped beads are usedy in building upother screens to meet cer- -tain requirements. These wafers with convexsurfaces do not-diffuse the light so cpmpletely as the smaller sphericalsurfaces but they admit of building a much thinner screen and there isless lossfof light by reflected light impinging on thev back of thebeads in the front layers.

When it is desiredtoplace the projection 6 3 apparatus behind thescreen, ,that is, on

the opposite side from that from which the spectators View the picture,it has been found advantageous/to use beads of a more translucentnature. For this ltype of back projec- .c5 tion the milkiness of the-beads is'reduced to such a'point that a large proportion of the.

-light is transmitted through the screen and prising clear. transparent,crystal beads is advantageous. Y

The beads are formed into a screen and held in proper relatively spacedposition in any appropriate manner. I have found it advantageous tosupport the various layers of beads upon Wire mesh fabric carefullyplacing the beads in spaced or contacting relation to each other bypermitting the beads to rest in the open meshes of the Wire mesh fabricand being supported by the lcrossed Wires thereof. The wire mesh fabric,during Wlll be no dlrect passage through the screen this operation, isstretched and supported in a horizontal position. A Wire mesh fabric isselected of such a mesh that the beads Will be supported by the crossedWires. rIhe wiresl of 'the wire mesh fabric being close enough togetherso that the beads will not fall through. 4` i Superimposed on this firstlayer of beads is placedV another wire mesh fabric of smaller mesh. Thebeads placed on this second wire mesh vfabric are smaller than thoseused in the first layer and are so placed on the meshes of the wirefabric that a bead is placed directly over each open space showingbetween beads of the first layer. Superimposed layers of beads are builtup this Way until a suflicient number. of layers has been added topreclude the passage throughth'e screen'of a direct ray of light withoutthe light strikinga bead. When this stage has been reached, ordinarilywith the placing of the third layer of beads, a final covering of wiremesh is put in place. This final covering of wire mesh .fabric ispreferably of the same mesh as the Wire mesh fabric supporting the last`layer of beads. The layers are then! permanently secured together in anyappropriate manner,

as-by means of tying together the two outer wire mesh fabrics -atfrequent intervals in both directions of the screen, that is',throughoutb the' length and breadth of the screen. This formation of aunitary mass or screen may also be accomplished by stitching 1either byhand or by machine. i

.Itis also contemplated to make use of ordiw narytextile fabrics inbuilding up the bead screen of the invention. Beads with holes orperforations are usually used with this type of fabric. lThe beads aresewed in place on thevfabr-ic by means of textile threads or fine wire.@nel or more' layers of beads may be sewed in place upon a singletextile fabric backing or one or more layers of fabrics with attachedbeads may be superimposed and appropriately sewed together.

Various materials are available for the beads used in building up thescreen of the invention. Glass beads prove most satisfactory Wheretransparency or' .translucency is desirable but other materials arequite satis-` factory for this type of bead. Bakelite, celluloid,cellulose acetate, casein and other plastic compositions of like naturefurnish satisfactory beads for screens of this ty e'. Beads of some ofthese materials may e formed directly in place upon the fabric andattached to the fabric by adhesionwhile still soft and plastic. Othersof these composition beads may be suitably attached by appropriatesolvents or mixtures of solvents and the material of which the beads arecomposed. Opaque beads may be composed of a great Variety of materialssuch for inst-ance as the" various metals and alloys. Ceramic materialsin great variety are also available for the making of opaque beads.Ceramic materials may be made with bothrglazed and unglazed faces andare available in a great variety of colorings or blended effects whichenhance the beauty of the reflected picture.

The practical operation andconstruction of a motion picture screenembodying thel aforementioned principles underlying the presentinventionwill be understood from the following descriptiontaken in'conjunction with the accompanying drawings, the various views of whichare greatly enlarged todepict more clearly the screen structures; inwhich,

Fig. 1 is a top plan of three layers bf the screen each shownseparately;

Fig. 2 is a sectional view of the screen with the same bead arrangement;and

Fig. 3 is a top diagrammatic representation of the same beadarrangement;

Fig. 4 is atop diagrammatic representation of another `three layer beadarrangement;

Fig. 5 is a top diagrammatic representation of still another three layerbead arrangement;

Fig. 6 is a sectional View of a bead screen built upon threelayers oftextile fabric.

The screen illustrated in Figs. '1, 2 and 8 comprises a wire mesh fabric`5' of diamond shaped meshes. The large sized beads 6 are supported inthe diamond shaped interstices of the wire mesh fabric 5 by theintersecting wires thereof. The beads of intermediate size are supportedin the dia-mond shaped interstices of the wire mesh fabric 7. The wiremesh fabric 7 and the beads 8 which it sup'- f in its interstices, bythe crossed wires of the mesh, the layer of smallest `sized beads 10. A

final wire mesh fabric covering 11 of the same mesh as the wire meshfabric 9 next vbelow is then placed'over the -top A` or last layer ofThe various layers of beads and wire mesh are then suitably fastenedtogether, as by securely tying the two outer wire mesh fabrics to eachother at regularly spaced intervals by means of threads `or wires 12.This tying together of the screen may be either done manually or bymachine stitching. When the various layers are thus consolidated into acoherent unitary screen the screen may be lifted into the uprightposition in which it is intended to be used. Y `The screendiagrammatically illustrated in Fig. 4 comprises a wire mesh fabric 13of square shaped meshes( Beads 14 of a diame-4 ter equal to the diagonalof the meshes of the Wire mesh fabric lf3 are placed in alternatesquares in the wiremesh fabric. By this arrangement the beads lie incontacting relation to each other in diagonalrows upon the wire meshfabric -and im spaced relation to each other in rows parallelto wires ofthe fabric. A Wire mesh fabric of the same size mesh is disposeddirectly over the first layer of beads in such a manner that the vwiresand openings are disposed directly over the wires and Openings of thefirst wire mesh fabrlc. A

similarlayer of beads 15 vis disposed on this vsecond wire mesh-fabricin such a manner that i Superimposed upon the third wire mesh is`- asmaller wire mesh fabric with square meshes of half of the size `of thewire mesh fabric previously used. Disposed upon alternate `squares'ofthis fabric are beads 16 of va diameter equal to'the diagonal lof thesquares of .the smaller wire mesh fabric. The beads in Athis third layerare so 'disposed that the centers of half of them \are directly over the-points of contact of ythe diagonal rows of beads'in the lower layers.As a consequence of this arrangement, the points at which the lowermeshes were stitched together are com- 'pletely covered by the upperlayer of smaller sized beads. A wire mesh fabric of the same mesh asthat used under this last vlayer is disposed upon the surface of thesmaller beads.

These two wire mesh fabrics are then ap- Y propriately stitchedytogether and the top unit appropriately attached to the lower two layersby stitching at suitable intervals. The screen diagrammaticallyillustrated in y Fig. 5 comprises three layers of beads dis' posed uponappropriate square wire mesh fabrics. The beads of each superimposedlayer are one half size of the beads in the layer the perforations ofthe bead. The various next below it. In each layer the beads aredisposedV in alternate meshes of the wire mesh fabric and the beads ofeach superimposing layer are disposed in such a manner that the openspaces left in the layer below it are suitably covered by the beads ofthe superimposing layer. The beads of each layer are substantially equalin diameter to the diagonal of thesquares of the wire mesh 10 fabric ,onwhich Ythey are disposed. Each layer is appropriately covered ywith awire r mesh fabric and the three layers are appropriately sewed togetherin such a manner as to form a unitary screen with the beads of theysmallest size on the spectator side of the screen. The screenillustratedin Fig. 6 comprises three layers of textile fabric 17.Perforated v beads are disposed on'each layer of fabric S3 in such amanner that the perforationslS in the beads lie parallel to the textilefabric. The beads of each layer are appropriately fastened to theVfabric by means of stitching 19 which passesthrough the fabric andthrough layers of the composite screen are stitched together atappropriate intervals by threads or wires 20. The/Various layers of thescreen are so disposed that beads of theI superim- 3 :posed layer liedirectly in front of the stitching used to attach the lower fabrics oneto another. rlhe side ofthe screen which is exposed to the spectator isthe layer of kbeads which'is not covered by a textile fabric.

Although Screens in accordance with the presentinvention may be made inthe manner described, I" do not wish to confine myself to these methodsalone. Screens in accordance with the present invention may be maderated articles onto long strings- These strings of beads or the like arethen placed parallel and woven into a fabric. In the weaving Y process4the strings of beads form the warp of .T the fabric and are stretchedlengthwise in the vloomt to be crossed by a woof which consists of finethreads of sufcicntstrength to form the Whole into a substantial fabricsuli'ciently strong for the purpose. Two or more of these fabrics maythen be 'suitably sewed together so that-there areI substantially nodirect passages therethrough for light and yet the nand frequently bywashing. Cleansing is an by Stringing beads or similar roundperforecast? i expensive operation and is only accomplished with greatcare by experts skilled in their trade. f A

Y The value of the screen asa motion picture screen will be understoodfrom the foregoing description as Well as its value in conjunction Withthe talking movies in the nature of the Vitaphone. When frontprojection'is being used, that is when the projection apparatus is placed on thespectator side of the screen, the sound producing horn or instrument maybe placed directly-behind the screen, and approximately at' its center.The sound from the horn will be transmitted directly through theinterstices of the screen and will appear `tothe spectators to emanatefrom the projected picture appearing on the screen.

lt is often necessaryor ,advisable during the showing of a picture touse talking or singing actors frequently in great numbers. Frequently`as high as one hundred and fifty voices have been used during theshowing of a picture. are often blurred by the opaque screen betweenthem and the audience. To overcome this diiiiculty the performers arecrowded over to the lateral edges ofthe opaque screen and their voicespermitted to pass through thin curtains hung at the sides of the motionpicture screen. Such a makeshift arrangement is unnecessary when usingthe screen of the invention. The singers Imay be disposed in lan orderlygrouping directly behind the porous screen and be invisible to theaudience penetrate the screen without -jects which are highly reiiectiveby nature and which due to their curved surfaces diduse the lightperfectly at every conceivable.A angle. Thus, although the visiblesurfac'eis made up of almost a perfect reflecting medium there is almosta complete absence of o glare and the projected picture will be equallydistinct when viewed from almost any an- There is some absorption oflight ingle.

The voices of these performers.

the beads of the screen, but this is no greater than the absorption oflight in the usual type vof screen.

Where back projection is desirable that is, where the projectionapparatus is placed on the opposite side of the screen from thespectators the present invention is also of imlil' y layer, and fixingthe and consequently the translucency of the bead permits of thetransmission through the screen of any predetermined quantity of light,thus any predetermined illumination of the projected picture may beobtained. This result is obtained without any loss of the soundtransmission quality of the Screen.

The translucent screen when made up of ruby or other suitable beads mabe advantageously used as a means of hghting the dark rooms used indeveloping and treating photographic materials which are injured byordinary light. Thus by placing such a screen at an opening in one sidelof a dark room'of this nature the injurious rays of light are cut olfand at the same time adequate ventilation is obtained directly throughthe porous screen itself.

When used as a motion picture screen the Screen of the invention hasmany desirable features which the heretofore customary screens do notafford, as, for instance, in the projection of colored or tintedpictures the eauty of the transmitted or refiected colors v -is muchenhanced over the heretofore customary methods due to the nature of beadmaterial.

I do not intend to confine myself -to the particular forms orarrangements that are shown in the accompanying drawings. These merelyillustra-te methods of arranging the relative position of the beads. Itwill be understood that a different arrangement of beads or a differentcombination `of 'wire mesh fabric and beads may be used withoutdeparting from the spirit of .the invention. The beads may be disposedupon the fabric in any suitable manner and-in any grouping arrangementwhich may seem best suited to existing conditions without departing fromthe spirit ofthe invention. Under certain circumstances and conditionsit may be found desirable to eliminate entirely the intermediate layersof wire mesh fabric employing onl the two outer wire mesh fabrics thusma ing desirable theuse of but a single size of bead. Each of thesearrangements permits of the -free passage of sound waves or air throughthe screen by means of the interstices between the beads.

I claim: L

1. The method of making screensfor projected pictures which comprisesarranging beads in layers, superimposing said layers of beads so thatthe beads of each succeeding layer cover the interstices of thepreceding said layers in said relation to each other. i

2. The method of making screens for projected pictures which comprisesarrangingV opaque beads in layers, superimposing said layers of opaquebeads so that the beads of each succeeding layer cover the intersticesof the preceding layer, and fixing the said layers 1n said relation tocach other.

3. A screen for "projecting pictures comprising a plurality of layers ofbeads, means for maintaining the beads of each layer in a predeterminedfixed relation to each other,`

4. A screen for projecting pictures comprising a plurality of layers ofbeads, the beads of adjacent layers being in contact with one another,means for maintaining the beads of each layer in a predetermined fixedrelation to each other, the beads in one layer overlying the intersticesin another layerso as to obstruct the direct passage of light throughthe screen but providing circuitous passageways for air therethrough,and means for securing said layers of beads together in sheet formation.

5. A screen for projected pictures comprising a plurality of layers ofbeads, and a plurality of layers of mesh fabric, the mesh of the fabricbeing smaller than the size ofthe beads, and means for tying said layersof fabric together with a layer of beads between each two layers offabric and with the beads of the rear layers staggered in relation tothe beads of the front layer thereby providing a surface which willreflect the entire area of the picture and at the same time havecircuitous sound passages therethrough.

6. A screen for projected pictures comprising a plurality of layers ofbeads, the beads of the innermost layer being closely positioned so asto substantially touch one another, and the beads of the other layer orhlayers being smaller than the beads of the innermost layer and spacedapart from one another suitably to cover the interstices of the beads ofthe innermost layer, and means for supporting said layers in fixedrelation to each other so that air and air borne sound Waves may betransmitted through the screen in the interstices between said beads andat the same time provide a surface which will project the entire area ofthe picture.

7. A screen for projected pictures comprising a plurality of sheets offabric each having a layer of beads secured thereto, and means.` forsecuring said sheets together thus forming the said layer of beads intoa uni-

